<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title></title>
	<style>
	.triangle_up {
		width: 0px;
		height: 0px;
		overflow: hidden;
		border-left: 10px solid transparent;
		border-right: 10px solid transparent;
		border-bottom: 10px solid red;
	}
	.triangle_down {
		width: 0px;
		height: 0px;
		overflow: hidden;
		border-left: 10px solid transparent;
		border-right: 10px solid transparent;
		border-top: 10px solid red;
	}
	.triangle_left {
		width: 0px;
		height: 0px;
		overflow: hidden;
		border-top: 10px solid transparent;
		border-bottom: 10px solid transparent;
		border-right: 10px solid red;
	}
	.triangle_right {
		width: 0px;
		height: 0px;
		overflow: hidden;
		border-top: 10px solid transparent;
		border-bottom: 10px solid transparent;
		border-left: 10px solid red;
	}
	</style>
</head>
<body>
	<div class="triangle_up"></div>	
	<br>
	<div class="triangle_down"></div>	
	<br>
	<div class="triangle_left"></div>	
	<br>
	<div class="triangle_right"></div>	
	<br>
</body>
</html>